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Purpose: This paper aims at developing an improved method, based on binary search algorithm (BSA) for the steady-state analysis of self-excited induction generators (SEIGs), which are increasingly used in wind energy electric conversion systems. The BSA is also compared with linear search algorithm (LSA) to bring out the merits of BSA over LSA. Design/methodology/approach: All the parameters of SEIG, including the varying core loss of the machine, have been considered to ensure accuracy in the predetermined performance values of the set up. The nodal admittance method has been adopted to simplify the equivalent circuit of the generator and load. The logic and steps involved in the formulation of the complete procedure have been illustrated using elaborate flowcharts. Findings: The proposed approach is validated by the experimental results, obtained on a three-phase 240 V, 5.0 A, 2.0 kW SEIG, which closely match with the corresponding predicted performance values. The analysis is shown to be easy to implement with reduced computation time. Originality/value: A novel improved and simplified technique has been formulated for estimating the per unit frequency (a), magnetizing reactance (Xm) and core loss resistance (Rm) of the SEIG using the nodal admittance of its equivalent circuit. The accuracy of the predetermined performance is enhanced by considering the SEIG's varying core loss. Only simple MATLAB programming has been used for adopting the algorithms. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to improve the control performance of wind energy conversion systems (WECSs) by proposing a new sensorless, robust control strategy based on a Smith predictor active disturbance rejection control (SP-ADRC) associated with a speed/position estimator. Design/methodology/approach: The estimator consists of a sliding mode observer (SMO) in combination with a phase-locked loop (PLL) to estimate the permanent magnet synchronous generator (PMSG) rotor position and speed. At the same time, the SP-ADRC is applied to the speed control loop of the variable-speed WECS control system to adapt strongly to dynamic characteristics under parameter uncertainties and disturbances. Findings: Numerical simulations are conducted to evaluate the speed tracking performances under various wind speed profiles. The results show that the proposed sensorless speed control improves the accuracy of rotor speed and position estimation and provides better power tracking performance than a regular ADRC controller under fast wind speed variations. Practical implications: This paper offers a new approach for designing sensorless, robust control for PMSG-based WECSs. Originality/value: A new sensorless, robust control is proposed to improve the stability and tracking performance of PMSG-based WECSs. The SP-ADRC control attenuates the effects of parameter uncertainties and disturbances and eliminates the time-delay impact. The sensorless control design based on SMO and PLL improves the accuracy of rotor speed estimation and reduces the chattering problem of traditional SMO. The obtained results support the theoretical findings. [ABSTRACT FROM AUTHOR]

• Control performance assessment (CPA) benchmark is built upon rational entropy (RE). • Dynamic data reconciliation is used to enhance the minimum RE control performance. • Probability function of non-Gaussian noise is estimated by Gaussian mixture model. • RE-CPA is more suitable for industrial processes with non-Gaussian noise. Control performance of the industrial process is inevitably influenced by the measurement noises and non-Gaussian external disturbances. This influence has not been fully considered in the traditional variance-based controller design. To reduce the influence, a novel scheme that can enhance the control performance is developed by integrating dynamic data reconciliation (DDR) into minimum rational entropy control (MREC) in this paper. Firstly, the influence of measurement noise is fully considered, and a novel DDR method is proposed to deal with the minimum entropy control (MEC) process such that the influence of measurement noise can be reduced, and the control performance will be improved. Then, based on the DDR-MREC performance index, a benchmark for evaluating the control performance of non-Gaussian systems is established. Finally, the proposed control performance assessment (CPA) method is applied to the wind energy conversion system and compared with the CPA method based on DDR-minimum variance control. The experimental results have demonstrated that the proposed new method is more effective than existing works. [ABSTRACT FROM AUTHOR]

This manuscript investigates the fuzzy memory sampled-data control (MSDC) scheme for the nonlinear permanent magnet synchronous generator (PMSG)-based wind energy conversion system (WECS) with quantization measurements. First, due to the complex nonlinearity, a Takagi-Sugeno (T-S) fuzzy modeling approach is successfully applied to the dynamics of nonlinear PMSG-based WECS. Second, by using the information of both quantized aperiodic sampling pattern and signal transmission delay, an H ∞ -based fuzzy quantized controller is put forward to ensure the stable performance as well as disturbance suppression index of the considered PMSG model by utilizing the refined looped Lyapunov functional (RLLF) approach. This RLLF perfectly utilizes more realistic information about the time derivative of the fuzzy membership function and actual sampling pattern. Then, two new integral inequalities are introduced to approximate the quadratic integral terms arising from the derivative of RLLF. Next, we establish some less conservative stabilization results in terms of linear matrix inequalities (LMIs) using the constructed RLLF, along with the proposed integral inequalities and fuzzy membership function-dependent (MFD) switching ideas. Finally, the simulation studies of PMGS-based WECS are validated numerically, and then a comparative example is provided to emphasize the superiority and relevance of the suggested approach. [ABSTRACT FROM AUTHOR]

The article looks at Vestas Wind Systems, focusing on its chief executive officer Ditlev Engel. The author notes that several companies in the U.S. wind industry have failed due to fluctuations in federal incentives being reliant on political agendas. The profitability of Vestas as a result of high oil prices is mentioned.

The article reports that the Iowa Association of Municipal Utilities plans to transform a sandstone aquifer beneath the state's Route 44 into a giant battery for storing energy from the wind. At night, when wind turbines produce unneeded power, the electricity will be used to compress air and pump it into the aquifer, creating a huge pressurized bubble. When demand for power rises, the compressed air will be piped backed to the surface where its energy will be converted into electricity.

Abstract This paper deals with a Wind Conversion System (WCS) based on a Hybrid Excitation Synchronous Generator (HESG) connected to an isolated load. The set is modeled under Matlab–Simulink. To ensure an efficient and reliable use of the system, a tight control remains vital. In fact, the dynamic equations of a turbine are strongly nonlinear as are the ones of a HESG; most of the system parameters are highly uncertain, and, at last, a WCS is always affected by disturbance sources such as load variances, harmonics, mechanical vibrations...To address these problems, robust control methods must be adopted. In this paper, two strategies for the control of variable speed wind turbine are investigated. First, an H ∞ controller is implemented. Then, a second-generation CRONE controller is designed. The performance of the two regulators is compared with respect to the tracking of the optimal rotation speed, the attenuation of the mechanical vibration and the robustness to the uncertainty of the parameters, using time-domain simulations. It has been found that the CRONE controller is more robust to parameters uncertainty and minimizes the fluctuations of the torsional torque and the generator's angular velocity. Finally, an experimental validation of the velocity controllers is presented to complete the simulation results and fully validate the chosen approach. [ABSTRACT FROM AUTHOR]

Abstract This paper presents a scaling methodology based on dimensional analysis and applicable to systems' mathematical models. The main goal of this research is to propose time-accelerated and size-scaled HIL (Hardware In the Loop) experiments, while keeping similarity with respect to the dynamics of the original system. The scaling process is presented using a simple wind turbine model. The scaling method is validated through simulations in which a wind turbine model and an electrochemical battery model are connected together. Finally, an experimental real-time validation is performed using physical emulators. [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to propose an improved direct torque control (DTC) for the induction motor's performance enhancement using dual nonlinear techniques. The exact feedback linearization is implemented to create a linear decoupled control. Besides, the fuzzy logic control approach has been inserted to generate the auxiliary control input for the feedback linearization controller. Design/methodology/approach: To improve the DTC for induction motor drive, this work suggests the incorporation of two nonlinear approaches. As the classical feedback linearization suffers while the presence of uncertainties and modeling inaccuracy, it is recommended to be associated to another robust control approach to compensate the uncertainties of the model and make a robust control versus the variations of the machine parameters. Therefore, fuzzy logic controllers will be integrated as auxiliary inputs to the feedback linearization control law. Findings: The simulation and the experimental validation of the proposed control algorithm show that the association of dual techniques can effectively achieve high dynamic behavior and improve the robustness against parameters variation and external disturbances. Moreover, the space vector modulation is used to preserve a fixed switching frequency, reduce ripples and low switching losses. Practical implications: The theoretical, simulation and experimental studies prove that the proposed control algorithm can be used on different AC machines for variable speed drive applications such as oil drilling, traction systems and wind energy conversion systems. Originality/value: The proposed DTC strategy has been developed theoretically and realized through simulation and experimental implementation. Different operation conditions have been conducted to check the ability and robustness of the control strategy, such as steady state, speed reversal maneuver, low-speed operation and parameters variation test with load application. [ABSTRACT FROM AUTHOR]

This paper addresses the distributed adaptive output-feedback tracking control problem of uncertain multi-agent systems in non-affine pure-feedback form under a directed communication topology. Since the control input is implicit for each non-affine agent, we introduce an auxiliary first-order dynamics to circumvent the difficulty in control protocol design and avoid the algebraic loop problem in control inputs and the unknown control gain problem. A decentralized input-driven observer is applied to reconstruct state information of each agent, which makes the design and synthesis extremely simplified. Based on the dynamic surface control technique and neural network approximators, a distributed output-feedback control protocol with prescribed tracking performance is derived. Compared with the existing results, the restrictive assumptions on the partial derivative of non-affine functions are removed. Moreover, it is proved that the output tracking errors always stay in a prescribed performance bound. The simulation results are provided to demonstrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

This paper proposes a sensorless fault-tolerant control strategy solving the tracking problem of the maximum delivered power characteristic for a wind energy conversion system equipped with a permanent magnet synchronous generator. A previously published control scheme ensuring the maximum power efficiency of the wind turbine, not requiring feedback information about rotor speed and position, and about wind velocity, is here extended to make the control scheme fault-tolerant with respect to possible electrical faults affecting the equations of the permanent magnet synchronous generator (PMSG) in the original ( α, β ) frame. The control law is based on a number of interconnected nonlinear observers. Closed loop asymptotic vanishing of the observation errors is proved. The proposed control solution has been validated on the National Renewable Energy Laboratory (NREL) 5-MW three-blade wind turbine model. [ABSTRACT FROM AUTHOR]

The article talks about various forms of wind power used to produce energy on land installation of wind turbine will need to have enough space. The power generated from the wind alone is not sufficient and it is recommended that wind be used as a backup to the cheaper option of solar. The height of the tower should be correct for turbine to work and Cliff Palmer, Principal at the Hesket Primary School in Victoria is going through that process now.

The article focuses on the supply and demand for renewable energy in the U.S. called wind power supply. Topics discussed include requirements for the installation of wind turbine project which include determination of wind-velocity of an area, analysis of climate variability, and knowing the supply and demand patterns of an area by the number of population.

Purpose – Doubly fed induction generator (DFIG) is widely used in wind energy conversion systems and it can operate with other primary movers. The purpose of this paper is to focus on the standalone operation of DFIG which may expand the area of possible applications and increase capabilities of the generation system in terms of power quality. Design/methodology/approach – Synthesis of the control method was preceded by analysis of mathematical model of the machine. The control method based on the negative sequence and high harmonics extraction has been developed and verified in the laboratory unit. Control of the fundamental frequency component uses neither rotor speed nor position sensors. Findings – The original method allows to compensate negative sequence and high harmonics of the generated voltage. At the same time, due to the active filtering capability of the grid side converter, the stator phase current shape is close to sine wave. Thus, it is seen by the machine as a linear load, what eliminates the electromagnetic torque ripples. Practical implications – The system and control method can be applied in variable speed generation systems, e.g. wind turbines or diesel engines operating in the standalone mode. Originality/value – Although the selective compensation of negative sequence and harmonics are known in the literature, until now the methods have been verified for the system with a rotor position sensor. Moreover, the stator current feed-forward improving the transient properties, as well as results of transient states caused by the load step change, have not been proposed in publications. [ABSTRACT FROM AUTHOR]

Purpose – The purpose of this paper is to investigate a control strategy to fulfill low-voltage ride through (LVRT) requirements in wind energy conversion system (WECS). Design/methodology/approach – This paper considers an active front-end converter of a grid connected WECS working under grid fault conditions. Two strategies based on symmetrical components are studied and proposed: the first one considers control only for positive sequence control (PSC); the second one considered a dual controller for positive and negative sequence controller (PNSC). The performance of each strategy is studied on LVRT requirements fulfillment. Findings – This paper shows presents a control strategy based on symmetrical component to keep the operation of grid-connected WECS under unsymmetrical grid fault conditions. Research limitations/implications – This work is being applied to a 2 kVA laboratory prototype. The lab prototype emulates a grid connected WECS. Originality/value – This paper validate the PNSC strategy to LVRT requirements fulfillment by experimental results obtained for a 2 kVA laboratory prototype. PNSC strategy allows constant active power delivery through grid-voltage dips. In addition, the proposed strategy is able to grid-voltage support by injection of reactive power. Additional features are incorporated to PNSC: sequence separation method using delay signal cancellation and grid frequency identification using phase locked loop. [ABSTRACT FROM AUTHOR]

This work studies the impact on power system dynamics of wind energy conversion systems based on permanent magnet synchronous generators when they perform ancillary services. The ability of modern variable-speed wind turbines to rapidly modify its active and reactive power is exploited in order to provide additional support to the power grid and enhance the overall stability of the system. A set of control loops are incorporated to the wind farm in order to achieve three supporting tasks: short-term frequency regulation, oscillation damping and voltage regulation. The analysis contemplates the effects of different loading conditions, measurement/communication time delays and control loop gains. Bifurcation diagrams, eigenvalue analysis and nonlinear time-domain simulations are used to assess the power system dynamics. The main contribution of this work is the assessment of wind farm ancillary services on the bifurcation structure of the power system. [ABSTRACT FROM AUTHOR]

The article focuses on the condition of the wind power market in the U.S. in 2012. It states that the country has showed roughly 13 gigawatts (GW) capacity of wind energy, representing 40 percent of all the energy installed in the year. It also mentions the data provided by the American Wind Energy Association (AWEA), which confirmed that nine states get 10 percent more of their electricity from wind. However, it also mentions the concern of the sector due to the upcoming expiration of the production tax credit (PTC), along with its last-minute renewal clarifications and qualification criteria.

The article offers information on several initiatives in Michigan committed to environmental protection including the environment advocacy group West Michigan Environmental Action Council (WMEAC), the Lake Michigan Offshore Wind Assessment Project and the Robert B. Annis Water Resources Institute. Topics discussed include the rain water conservation Rain Barrel project of WMEAC, wind energy development project at Lake Michigan, and projects to preserve and enhance fresh water resources.

The article presents information on the development of wind energy in the U.S. which has mainly reduced the dependence on fossil fuels and the overall carbon emissions. A focus is on the reliability of the electric grids and the weaknesses in the U.S. transmission system. The primary obstacles in developing robust transmission system include nature of renewable resources, electric grid flexibility and cost allocations issues.

Purpose - Wind energy plays a very important role in the future electrical power supply. With growing shares, the focus of the plant control will have to shift from maximum power yield to grid friendly aspects, like stable power output despite fluctuating wind power. The purpose of this paper is to design a new operation management for wind energy converters that combines high-energy yield, grid friendly power output characteristics and the ability to adapt to changing wind conditions. Design/methodology/approach - An operation control based on stochastic dynamic optimization was developed for the special demands of variable speed wind energy converters. The task of the operation control is to set the appliance to the optimal operation point, following the above-mentioned goals by adapting the control pattern to changing wind conditions. Findings - It is shown that the novel control concept, the iterative self-adapting system management with stochastic dynamic optimization, is able to control wind energy converters in such a way that the effect of the stochastic fluctuating wind energy supply on the output power fluctuation is smoothed while maintaining a high-energy yield. Originality/value - This non-linear stochastic dynamic optimization structure has two special characteristics, first is the iterative self-adaptation, and second is the optimization for an infinite process, while the optimization criteria are high-power yield and low-power output fluctuations. This will be of great value for further increase of wind energy converters in the electrical power supply. [ABSTRACT FROM AUTHOR]

The article offers information on the advantages offered by wind power in the U.S. Due to the rising cost of petroleum products, the government is searching for another alternative source of power and one of these is the wind power. In 2007, 35% of all the new electricity generation installed in the country came from wind power. In September 2008, the country surpassed Germany to lead the world in wind energy production, providing more than 20,000 Megawatts (MW) of generating capacity, which is enough to serve 5.3 million homes or to power one million plug-in hybrid vehicles. To further is benefits, the government passed the new energy bill, wherein wind power is on track to reach the 30,000 MW milestone in 2009.

To assess the wind power resources of a large continental shelf area, we analyze the 18-year hourly wind records from meteorological stations in the US Middle Atlantic Bight (MAB), comparing areas of coast, estuary, and open shelf. We calculate winds at turbine hub height for the sea breeze compared with synoptic winds and, for each type of site, we compare the seasonal and daily phase match to electrical load. To improve large-scale ocean power resource calculations, we derive an iterative algorithm to determine the surface roughness coefficient (z0). Our method calculates z0 for specific times and locations over the ocean, rather than the prior practice of using a generic z0 that is constant across time and space. Due to lower surface roughness of the ocean, wind speeds are notably higher at hub height, so that in the MAB we find that a representative open shelf site has three times the power content of a nearby land site. Regarding phase match to daily electric load, we find the sea breeze adjacent to the coast is a very good match to this region's electric power load profile. However, the open shelf wind speeds are so much higher (10.9 m s-1 versus 5.7 m s-1 for the comparison period) that the near-coast phase advantage is obviated. We also find more consistent wind power production offshore, with single sites producing at least some power 88 to 92% of the time. By modeling electrically interconnected sites, power production improves to 96.3% with as few as three interconnected wind sites and to 99.3% with 5 interconnected sites. [ABSTRACT FROM AUTHOR]

Discusses renewable energy. Current supply in the United States; Tapping of renewable sources such as the sun and the wind; Geothermal energy use in western U.S. states; Long-term outlook for energy sources; Renewable energy technology opportunities.

The article provides information on the emerging wind energy projects that can provide higher electrical efficiency and performance at lower costs. It states that the Solar Energy Research Institute (SERI) in Colorado has contracted wind research programs for the U.S. Department of Energy. It adds that SERI's Richard Mitchell has said that not all wind turbine concepts are viable but others have the potential for wind-energy conversion and improved turbine performance.

The article discusses the author's assessment for the 33 wind generator variations in the market. He suggests the use of inter-tie wind generator connections which works without the batteries. He also examines the capacity and reliability of an induction-type wind generator. A table which shows all the 33 wind generators with their own specifications were also presented.

The author focuses on the need to harness solar, wind and geological sources of energy for power and heating requirements of a house or business enterprises. Topics discussed include the use of energy generated by ground source heat pumps (GSHP) for hot water and heating systems, horizontal/vertical axis (HAWT/VAWT) types of wind turbines and generation of electricity from light by photo voltaics (PV).

The article discusses the importance for wind farm developers to consider the environmental conditions that might affect the operation of their investments in the U.S. It suggests the need for developers to carefully choose the right control systems that are essential to the turbine's operation and safety since most of them are located in outdoor and potentially harsh environments. It also advises developers to provide backup power to their utility power source to ensure that the reliability of their power source. Moreover, it also recommends to consider choosing the right blade speed and braking systems that control the output frequency in high wind conditions.

The article focuses on wind power. Wind energy has become an increasingly significant means of generating electric power, with world capacity growing at approximately 30 percent a year. It is forecast that wind power could generate as much as 15 percent of U.S. electricity by 2020. The financial advantages of building wind farms as opposed to conventional electric power plants are detailed.

Focuses on ways to connect solar or wind systems to grid-tied homes. Components of direct-tie installations; Voltage consumption of battery-based systems; Techniques in establishing grid parallel systems.

The article discusses a windmill prototype developed by the company FloDesign Wind Turbine which utilizes features present in jet engines. The article notes that the prototype is believed to be three times more efficient at producing electricity than three-bladed windmills. According to the author some experts suggest that the prototype could transform the wind industry.

The article explains how scientists have created computers that are able to use the techniques of kite surfing in order to harness an optimal amount of wind energy. This method of collecting energy from the wind is thought to add another option to the harnessing of renewable resources. The author explains that the computers use various algorithms which create figure of eight patterns to harness the greatest amount of wind energy.

The article discusses a study by the University of Delaware and Stanford University which states that there is enough wind off the U.S. Atlantic coast between Massachusetts and North Carolina to power that area. The study also showed that the potential power that could be generated by the winds is four times the area's existing generating capacity. The study excludes deepwater and off-limit zones such as commercial shipping lanes and spots visible from tourist beaches.

The article presents information on various developments related to health and environment. A private consortium has applied for permission to build a massive wind farm near London. The proposed farm, 25 kilometres off the Essex coast, would have 270 turbines and be capable of generating 1000 megawatts, 1 per cent of Great Britain's energy needs, or enough for 750,000 homes. In another development, for the first time, a woman has given birth as a result of an ovarian transplant. Stephanie Yarber, aged 25, of Montgomery, Alabama, gave birth to her daughter Anna on June 6 after having a slice of one of her identical twin's ovaries transplanted in April last year.

The article focuses on the opening of Block Island Wind Farm, the first offshore wind plant in the U.S. It is stated that Block Island Wind Farm is the first plant of its kind in the nation although offshore wind energy has been used in Europe since 1991. It is mentioned that took several weeks over the summer to install the turbines for the Block Island Wind Farm due to some unique challenges compared with turbines on land.

The article focuses on the technology SkyMill that is used to harvest high altitude wind energy using the phenomenon of Aero-Rotors' autorotation. Topics discussed include production of relative wind energy from atmospheric wind; attachment of SkyMill to ground generation device by tether that helps to produce potential energy by tension; attributes of SkyMill such as technological independence, and production of energy many times better than ground wind turbines.

The article talks about the role of wind energy, its impact in preventing climate change and the investment by nations in clean energy supplies and reducing carbon intensive technologies including the actions taken by Australia towards renewable energy investments and becoming a low carbon economy.

The article discusses the design and development of a portable wind turbine unit capable of generating electricity from the kinetic energy in the wind. Tools used include miniature DC motor, wind turbine blades/propeller, and DC-DC boost converter. Other factors discussed include good air flow, pulse frequency modulation converter, and electric air blower as the wind-energy source for testing purposes.

The article focuses on generation of wind power on a personal scale using smaller devices. Topics discussed are use of small scale windmills to generate power for remote sensors, use of piezoelectric material to generate electric current by a student Akhilesh Balasingam, and student Rachel Pizzolato's windmill to generate power from the wind due to passing of vehicles on the road.

The article presents information on two wind technologies that can generate electricity even when the air is still. It discusses the use of fossil fuels to generate electricity in the U.S., and the design features of the BAT wind turbine developed by Altaeros Energies and the Solar Wind Downdraft Tower developed by Solar Wind Energy Inc.

The article focuses on the report "What's Next for Alternative Energy?" issued by the consulting company Boston Consulting Group Inc. on the use of concentrated solar power (CSP) for electricity generation in Pakistan. According to the report, CSP technology could provide electricity at 0.10 U.S. dollar or even less per kilowatt-hour by 2020. It discusses the wind energy research project at Pakistan Navy Engineering College that will start the compilation of the second phase wind data in 2014.

The article offers information related to the New York State Research and Development Authority (NYSERDA), and Department of Health. It says that the Empire State Stem Cell Board (ESCB) is calling for applications for their funding of research in stem cell biology, which they will use to explore stem cell properties for treating diseases. It adds that NYSERDA is offering $13.8 million in incentives for end-use wind energy systems installation in residential, government, and commercial use.

The article discusses implementation of a programme to promote installation of Small Wind Energy and Hybrid Systems in Tamil Nadu, India by Indian Ministry of New and Renewable Energy while mentioning a pilot-cum-demonstration project at the National Institute of Wind Energy at Kayathar.

The article offers advantages of midsize wind projects compared to capital-intensive projects in the U.S. Community-wind advocates promote midsize projects, comprising of two to five megawatts (MW), because it believed that it offers many advantages over capital-intensive, corporate-owned wind farms. It was found that several geographically diverse and interconnected midsize installation can make better use of wind resources compared to hat of single large utility-scale wind farm. Research shows that a Minnesota legislature-commissioned study found that wider distribution of wind production could reduce the time when little or no power is being produced. It could also help operators manage sharp increases in power when wind suddenly picks up, resulting in a more stable electricity supply.

The article focuses on the plans of the company Taro Pharma to launch wind power projects in the U.S. has been shelved for the moment which was seconded by pharmaceutical company Sun Pharma.

The article reports on the research conducted by Soji Adeleja and John A Hannah of the Michigan State University regarding the importance of windmills in Michigan. Researchers will assess and evaluate the wind power that could be generated by a variety of wind fields and its implication in increasing the state's current wind power capacity. They found that the state houses 40% of the Great Lakes watersurface area and ranks 14th in the country with respect to onshore wind resources. When utilized efficiently and effectively, the energy generated by these windmills could dramatically increase the state's current wind power capacity.

This article reports on an innovative approach to wind power in Russia. Laurie Chetwood has designed a giant sail that he claims will be much more efficient that traditional turbines. Two aluminum legs support the 17,000-square-foot Kevlar sail. which is anchored to cliffs in a valley near Lake Ladoga.

The author reports on research being done by engineer Louis Michaud regarding wind energy. Michaud's goal is to transform tornadoes into power plants by creating a vortex of hot air which is able to produce enough electricity to power thousands of homes. Criticisms which have been raised in regards to Michaud use of wind energy are mentioned. A description of how vortex energy works is given.

The article discusses the efforts taken in several states in the U.S. to install wind generators in urban areas. Some of the organizations that are introducing windpower for metropolitan areas include Southwest Windpower and AeroVironment. However, according to the author, the urban environment is less hospitable to wind power.

The article focuses on alternative energy, in particular harnessing artificial tornadoes as an energy source. The energy released by a large hurricane can exceed the energy consumption of the human race for a whole year, and even an average tornado has a power similar to that of a large power station. Louis Michaud, a Canadian engineer who works at a large oil company, believes he has devised a way to do just that, by generating artificial whirlwinds that can be controlled and harnessed. He calls his invention the "atmospheric vortex engine". Besides the engineering challenges involved, Michaud must navigate the cultural divide between atmospheric scientists and the weather-modification community. Michauud has published nine papers in atmospheric-science and meteorology journals, and says his invention relies on principles that are consistent with scientists' current understanding of how natural weather systems work.